Telecommunications system cooling fan incorporating a compact vibration isolator

ABSTRACT

The present invention provides a cooling fan assembly for use in a telecommunications system, including: a cooling fan; a housing; a rigid pin disposed through the housing an into a mounting hole manufactured into the cooling fan; a vibration isolator disposed about the rigid pin within the mounting hole; and a washer disposed about the rigid pin between the cooling fan and the housing. The vibration isolator is a cylindrical vibration isolator. The vibration isolator is made of a polymeric vibration damping material. The washer is made of material with a low coefficient of friction. The vibration isolator is operable for damping vibrations emanating from the cooling fan. The washer is operable for allowing some movement of the cooling fan perpendicular to the rigid pin.

FIELD OF THE INVENTION

The present invention relates generally to a telecommunications system cooling fan. More specifically, the present invention relates to a telecommunications system cooling fan incorporating a compact vibration isolator.

BACKGROUND OF THE INVENTION

Vibration induced connector damage is common on the cooling units and associated backplane connectors used in telecommunications systems. Typical vibration mitigation strategies involve the use of dampers or bushings that are added to the mounting points of the cooling fans, typically above and below the cooling fans. This, however, requires an increase in the size of the cooling units. If space is not available within the broader telecommunications system, then dimensions must be enlarged, and a full redesign must be undertaken, resulting in significant delay and expense. Further, valuable space must be allocated which may be reserved for other functions and a full redesign is not an option for already deployed telecommunications systems.

Thus, what is still needed in the art is a compact vibration isolator that works with existing cooling units and conserves valuable space.

BRIEF SUMMARY OF THE INVENTION

In various exemplary embodiments, the present invention provides a cooling fan that incorporates a compact vibration isolator including a rigid pin, a low-friction washer, and a cylindrical vibration isolator. This compact vibration isolator is used at each connection point between the cooling fan and the associated chassis. Collectively, these compact vibration isolators allow the cooling fan to move freely within the chassis without the conduction of vibration to the housing of the cooling unit, while dissipating the energy of any vibration. The compact vibration isolators mount almost entirely within the cooling fans mounting holes, allowing them to be used in cooling units in which space has not been allocated for conventional vibration isolators, such as elastomer pads or bumpers. The compact vibration isolators work in any orientation, allowing them to be used with cooling units that are installed in multiple orientations.

In one exemplary embodiment, the present invention provides a cooling fan assembly for use in a telecommunications system, including: a cooling fan; a housing; a rigid pin disposed through the housing an into a mounting hole manufactured into the cooling fan; a vibration isolator disposed about the rigid pin within the mounting hole; and a washer disposed about the rigid pin between the cooling fan and the housing. The vibration isolator is a cylindrical vibration isolator. The vibration isolator is made of a polymeric vibration damping material. The washer is made of a material with a low coefficient of friction. The vibration isolator is operable for damping vibrations emanating from the cooling fan. The washer is operable for allowing some movement of the cooling fan perpendicular to the rigid pin.

In another exemplary embodiment, the present invention provides a method for providing a cooling fan assembly for use in a telecommunications system, including: providing a cooling fan; providing a housing; disposing a rigid pin through the housing an into a mounting hole manufactured into the cooling fan; disposing a vibration isolator about the rigid pin within the mounting hole; and disposing a washer about the rigid pin between the cooling fan and the housing. The vibration isolator is a cylindrical vibration isolator. The vibration isolator is made of a polymeric vibration damping material. The washer is made of a material with a low coefficient of friction . The vibration isolator is operable for damping vibrations emanating from the cooling fan. The washer is operable for allowing some movement of the cooling fan perpendicular to the rigid pin.

In a further exemplary embodiment, the present invention provides a cooling fan vibration isolator for use in a telecommunications system, including: a rigid pin disposed through a housing an into a mounting hole manufactured into a cooling fan; a vibration isolator disposed about the rigid pin within the mounting hole; and a washer disposed about the rigid pin between the cooling fan and the housing. The vibration isolator is a cylindrical vibration isolator. The vibration isolator is made of a polymeric vibration damping material. The washer is made of a material with a low coefficient of friction. The vibration isolator is operable for damping vibrations emanating from the cooling fan. The washer is operable for allowing some movement of the cooling fan perpendicular to the rigid pin.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated and described herein with reference to the various drawings, in which like reference numbers are used to denote like system components/method steps, as appropriate, and in which:

FIG. 1 is a perspective view of one exemplary embodiment of the cooling unit of the present invention;

FIG. 2 is a perspective view of one exemplary embodiment of the compact vibration isolator of the present invention;

FIG. 3 is a cross-sectional view of one exemplary embodiment of the compact vibration isolator of the present invention;

FIG. 4 is a cross-sectional view of one exemplary embodiment of the cooling unit of the present invention;

FIG. 5 is a planar view of one exemplary embodiment of the cooling unit of the present invention;

FIG. 6 is a block diagram illustrating an exemplary node for use with the systems and methods described herein; and

FIG. 7 is a block diagram illustrating a controller to provide control plane processing and/or operations, administration, maintenance, and provisioning (OAM&P) for the node of FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

Again, in various exemplary embodiments, the present invention provides a cooling fan that incorporates a compact vibration isolator including a rigid pin, a low-friction washer, and a cylindrical vibration isolator. This compact vibration isolator is used at each connection point between the cooling fan and the associated chassis. Collectively, these compact vibration isolators allow the cooling fan to move freely within the chassis without the conduction of vibration to the housing of the cooling unit, while dissipating the energy of any vibration. The compact vibration isolators mount almost entirely within the cooling fans mounting holes, allowing them to be used in cooling units in which space has not been allocated for conventional vibration isolators, such as elastomer pads or bumpers. The compact vibration isolators work in any orientation, allowing them to be used with cooling units that are installed in multiple orientations.

Referring now specifically to FIGS. 1-4, in one exemplary embodiment, the cooling unit 10 includes a cooling fan 12 that is disposed within a fan housing 14. A compact vibration isolator 16 is disposed at each fan mounting point (of which there are typically eight (8)). Each compact vibration isolator 16 includes a metallic or rigid pin 18 that is press fit into or otherwise disposed through the fan housing 14. In one exemplary embodiment, this pin 18 has a length of between about 4 mm and about 10 mm. A low-friction washer 20 is disposed about the base of each pin 18. Preferably, this washer 20 is made from a material with a low coefficient of friction. In one exemplary embodiment, the washer 20 has an outer diameter of between about 5 mm and about 10 mm. A cylindrical vibration isolator 22 is then disposed about the pin 18. Preferably, this vibration isolator 22 is made from a polymeric vibration damping material. In one exemplary embodiment, the vibration isolator 22 has an outer diameter of between about 2.4 mm and about 4 mm. Although a “cylindrical” vibration isolator is illustrated and described herein, it will be readily apparent to those of ordinary skill in the art that other shapes or configurations may be used. This assembly is used at each fan mounting point. The cooling fan 12 is then disposed over the vibration isolators 16.

Referring now specifically to FIG. 5, it can be seen that the low-friction washers 20 (FIGS. 2 and 3) allow the fan 12 to move freely without the conduction of vibration to the housing 14 of the cooling unit 10, while the vibration isolators 22 dissipate the vibrational energy.

As discussed herein above, cooling fans are typically mounted to the chassis of a cooling unit using metallic screws or the like. This type of connection couples the vibration of the fan to the chassis and the rest of the telecommunications system. Under certain circumstances, this vibration can cause damage and premature failure of various components, and particularly connectors. Conventional vibration isolators consist of pads or other isolators that are disposed between the fan and the chassis, requiring significantly more space than the washers of the present invention.

Experiments have demonstrated that vibration generated by the fans within the plane of impeller rotation is of chief concern with respect to connector wear. Therefore, damping in the vertical direction is less critical. Placing only a very thin, low-friction washer between the fan and the chassis allows the fan to move from side to side without exerting a significant force on, or inducing vibration in, the chassis. The compliant isolator of the present invention instead damps the motion and prevents it from being transmitted to the chassis and the rest of the telecommunications system. The pin provides a mounting point for the washer and the isolator and prevents larger displacements of the fan.

Advantageously, the present invention locates most of the isolator within the mounting holes of the fan. The only part of the assembly that is external to the fan is the washer, which is manufactured to be negligibly thin compared to other components in the assembly. This allows the compact vibration isolator of the present invention to be used without taking up any additional system volume.

Vibration-induced connector damage is non-trivial and is the leading reason for communication loss with cooling units. Such connector damage may be rectified by replacing an affected cooling unit, but backplane connectors are not so easily replaced. Thus, this is a significant issue.

Referring now specifically to FIG. 6, in one exemplary embodiment, an exemplary node or shelf with which the fan assembly of the present invention may be used is illustrated. The node can be a network element that may consolidate the functionality of a multi-service provisioning platform (MSPP), digital cross connect (DCC), Ethernet and/or Optical Transport Network (OTN) switch, dense wavelength division multiplexed (DWDM) platform, etc. into a single, high-capacity intelligent switching system providing Layer 0, 1, and/or 2 consolidation. In another exemplary embodiment, the node can be any of an OTN add/drop multiplexer (ADM), a multi-service provisioning platform (MSPP), a digital cross connect (DCC), an optical cross connect (OXC), an optical switch, a router, a switch, a wavelength division multiplexing (WDM) terminal, an access/aggregation device, etc. That is, the node can be any digital system with ingress and egress digital signals and switching therebetween of channels, timeslots, tributary units, etc. utilizing OTN, etc. While the node is generally shown as an optical network element, the systems and methods contemplated are for use with any switching fabric, network element, or network based thereon.

In an exemplary embodiment, the node includes common equipment, one or more line modules, and one or more switch modules. The common equipment can include power; a control module; operations, administration, maintenance, and provisioning (OAM&P) access; user interface ports; and the like. The common equipment can connect to a management system through a data communication network (as well as a PCE, SDN controller, OpenFlow controller, etc.). The management system can include a network management system (NMS), element management system (EMS), or the like. Additionally, the common equipment can include a control plane processor configured to operate the control plane. The node can include an interface for communicatively coupling the common equipment, the line modules, and the switch modules therebetween. For example, the interface can be a backplane, mid-plane, a bus, optical or electrical connectors, or the like. The line modules are configured to provide ingress and egress to the switch modules and external to the node. In an exemplary embodiment, the line modules can form ingress and egress switches with the switch modules as center stage switches for a three-stage switch, e.g. a three stage Clos switch. Other configurations and/or architectures are also contemplated. The line modules can include optical transceivers, such as, for example, 1 Gb/s (GbE PHY), 2.5 Gb/s (OC-48/STM-1, OTU1, ODU1), 10 Gb/s (OC-192/STM-64, OTU2, ODU2, 10GbE PHY), 40 Gb/s (OC-768/STM-256, OTU3, ODU3, 40GbE PHY), 100 Gb/s (OTU4, ODU4, 100GbE PHY), ODUflex, etc.

Further, the line modules can include a plurality of optical connections per module and each module may include a flexible rate support for any type of connection, such as, for example, 155 Mb/s, 622 Mb/s, 1 Gb/s, 2.5 Gb/s, 10 Gb/s, 40 Gb/s, and 100 Gb/s, N×1.25 Gb/s, and any rate in between. The line modules can include wavelength division multiplexing (WDM) interfaces, short reach interfaces, and the like, and can connect to other line modules on remote network elements, end clients, edge routers, and the like. From a logical perspective, the line modules provide ingress and egress ports to the node, and each line module can include one or more physical ports. The switch modules are configured to switch channels, timeslots, tributary units, etc. between the line module. For example, the switch modules can provide wavelength granularity (Layer 0 switching), SONET/SDH granularity such as Synchronous Transport Signal-1 (STS-1) and variants/concatenations thereof (STS-n/STS-nc), Synchronous Transport Module level 1 (STM-1) and variants/concatenations thereof, Virtual Container 3 (VC3), etc.; OTN granularity such as Optical Channel Data Unit-1 (ODU1), Optical Channel Data Unit-2 (ODU2), Optical Channel Data Unit-3 (ODU3), Optical Channel Data Unit-4 (ODU4), Optical Channel Data Unit-flex (ODUflex), Optical channel Payload Virtual Containers (OPVCs), ODTUGs, etc.; Ethernet granularity; Digital Signal n (DSn) granularity such as DS0, DS1, DS3, etc.; and the like. Specifically, the switch modules 630 can include both Time Division Multiplexed (TDM) (i.e., circuit switching) and packet switching engines. The switch modules can include redundancy as well, such as 1:1, 1:N, etc. In an exemplary embodiment, the switch modules provide OTN switching and/or Ethernet switching.

Those of ordinary skill in the art will recognize the node can include other components which are omitted for illustration purposes, and that the systems and methods described herein are contemplated for use with a plurality of different network elements with the node presented as an exemplary type of network element. For example, in another exemplary embodiment, the node may not include the switch modules, but rather have the corresponding functionality in the line modules (or some equivalent) in a distributed fashion. For the node, other architectures providing ingress, egress, and switching therebetween are also contemplated for the systems and methods described herein. In general, the systems and methods described herein contemplate use with any network element providing switching of OTN channels, timeslots, tributary units, wavelengths, etc. Furthermore, the node is merely presented as one exemplary node for the systems and methods described herein. Further the WDM functionality can be included in the node or in a separate node.

Referring now specifically to FIG. 7, in one exemplary embodiment, a controller is illustrated to provide control plane processing and/or operations, administration, maintenance, and provisioning (OAM&P) for the node. The controller can be part of common equipment, such as common equipment in the node, or a stand-alone device (e.g., a PCE) communicatively coupled to the node via the DCN. The controller can include a processor which is hardware device for executing software instructions such as operating the control plane. The processor can be any custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the controller, a semiconductor-based microprocessor (in the form of a microchip or chip set), or generally any device for executing software instructions. When the controller is in operation, the processor is configured to execute software stored within memory, to communicate data to and from the memory, and to generally control operations of the controller pursuant to the software instructions. The controller can also include a network interface, a data store, memory, an I/O interface, and the like, all of which are communicatively coupled therebetween and with the processor.

The network interface can be used to enable the controller to communicate on the DCN, such as to communicate control plane information to other controllers, to the management system, and the like. The network interface can include, for example, an Ethernet card (e.g., 10BaseT, Fast Ethernet, Gigabit Ethernet) or a wireless local area network (WLAN) card (e.g., 802.11a/b/g). The network interface can include address, control, and/or data connections to enable appropriate communications on the network. The data store can be used to store data, such as control plane information, provisioning data, OAM&P data, etc. The data store can include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, and the like)), nonvolatile memory elements (e.g., ROM, hard drive, flash drive, CDROM, and the like), and combinations thereof. Moreover, the data store can incorporate electronic, magnetic, optical, and/or other types of storage media. The memory can include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), nonvolatile memory elements (e.g., ROM, hard drive, flash drive, CDROM, etc.), and combinations thereof. Moreover, the memory may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory can have a distributed architecture, where various components are situated remotely from one another, but may be accessed by the processor. The I/O interface includes components for the controller to communicate to other devices. Further, the I/O interface includes components for the controller to communicate with the other nodes, such as using overhead associated with OTN signals.

It will be appreciated that some exemplary embodiments described herein may include one or more generic or specialized processors (“one or more processors”) such as microprocessors, digital signal processors, customized processors, and field programmable gate arrays (FPGAs) and unique stored program instructions (including both software and firmware) that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the methods and/or systems described herein. Alternatively, some or all functions may be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic. Of course, a combination of the aforementioned approaches may be used. Moreover, some exemplary embodiments may be implemented as a non-transitory computer-readable storage medium having computer readable code stored thereon for programming a computer, server, appliance, device, etc. each of which may include a processor to perform methods as described and claimed herein. Examples of such computer-readable storage mediums include, but are not limited to, a hard disk, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a PROM (Programmable Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), Flash memory, and the like. When stored in the non-transitory computer readable medium, software can include instructions executable by a processor that, in response to such execution, cause a processor or any other circuitry to perform a set of operations, steps, methods, processes, algorithms, etc.

Although the present invention is illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present invention, are contemplated thereby, and are intended to be covered by the following claims. 

What is claimed is:
 1. A cooling fan assembly for use in a telecommunications system, comprising: a cooling fan; a housing; a rigid pin disposed through the housing an into a mounting hole manufactured into the cooling fan; a vibration isolator disposed about the rigid pin within the mounting hole; and a washer disposed about the rigid pin between the cooling fan and the housing.
 2. The cooling fan assembly of claim 1, wherein the vibration isolator comprises a cylindrical vibration isolator.
 3. The cooling fan assembly of claim 1, wherein the vibration isolator comprises a polymeric vibration damping material.
 4. The cooling fan assembly of claim 1, wherein the washer comprises a material with a low coefficient of friction.
 5. The cooling fan assembly of claim 1, wherein the vibration isolator is operable for damping vibrations emanating from the cooling fan.
 6. The cooling fan assembly of claim 1, wherein the washer is operable for allowing some movement of the cooling fan perpendicular to the rigid pin.
 7. A method for providing a cooling fan assembly for use in a telecommunications system, comprising: providing a cooling fan; providing a housing; disposing a rigid pin through the housing an into a mounting hole manufactured into the cooling fan; disposing a vibration isolator about the rigid pin within the mounting hole; and disposing a washer about the rigid pin between the cooling fan and the housing.
 8. The cooling fan assembly method of claim 7, wherein the vibration isolator comprises a cylindrical vibration isolator.
 9. The cooling fan assembly method of claim 7, wherein the vibration isolator comprises a polymeric vibration damping material.
 10. The cooling fan assembly method of claim 7, wherein the washer comprises a material with a low coefficient of friction.
 11. The cooling fan assembly method of claim 7, wherein the vibration isolator is operable for damping vibrations emanating from the cooling fan.
 12. The cooling fan assembly method of claim 7, wherein the washer is operable for allowing some movement of the cooling fan perpendicular to the rigid pin.
 13. A cooling fan vibration isolator for use in a telecommunications system, comprising: a rigid pin disposed through a housing an into a mounting hole manufactured into a cooling fan; a vibration isolator disposed about the rigid pin within the mounting hole; and a washer disposed about the rigid pin between the cooling fan and the housing.
 14. The cooling fan vibration isolator of claim 13, wherein the vibration isolator comprises a cylindrical vibration isolator.
 15. The cooling fan vibration isolator of claim 13, wherein the vibration isolator comprises a polymeric vibration damping material.
 16. The cooling fan vibration isolator of claim 13, wherein the washer comprises a material with a low coefficient of friction.
 17. The cooling fan vibration isolator of claim 13, wherein the vibration isolator is operable for damping vibrations emanating from the cooling fan.
 18. The cooling fan vibration isolator of claim 13, wherein the washer is operable for allowing some movement of the cooling fan perpendicular to the rigid pin. 